Coordination Polymer Proton Conductor for Dry Fuel Cell Catalysts
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Solution Overview
Problem
Current medium temperature dry fuel cells operating at 100° C or more under non-humidified conditions face a decrease in power generation performance due to platinum catalyst poisoning and low proton transport numbers when using phosphoric acid-doped polybenzimidazole proton conductors, which results in reduced electromotive force and catalytic activity.
Innovation Solution
A proton conductor is developed that includes a cationic organic molecule, a metal ion, and an oxoacid anion forming a coordination polymer, where the protic ionic liquid is coordinated to the metal ion, enhancing proton transport and suppressing platinum poisoning, thereby maintaining power generation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If phosphoric acid-doped polybenzimidazole proton conductor is used, then the fuel cell can operate at medium temperature (100°C or more) under non-humidified conditions, but the proton transport number decreases and platinum catalyst poisoning occurs
Solution Approach 1:
The patent employs a composite proton conductor material consisting of polybenzimidazole polymer matrix doped with phosphoric acid and incorporating metal organic framework (MOF) structures. This composite structure combines the thermal stability of the polymer with the high proton conductivity of the MOF, achieving both medium-temperature operation and maintained proton transport number. The MOF channels provide dedicated proton conduction pathways that prevent catalyst poisoning while enabling operation at 100°C or above.
2Temperature
If phosphoric acid-doped polybenzimidazole proton conductor is used, then the fuel cell can operate at medium temperature (100°C or more) under non-humidified conditions, but catalytic activity decreases due to platinum poisoning
Solution Approach 1:
The metal organic framework (MOF) structure acts as an intermediary between the phosphoric acid dopant and the platinum catalyst. The MOF channels provide a controlled environment that facilitates proton transport while physically separating the phosphoric acid from direct contact with the platinum catalyst surface. This intermediary structure prevents catalyst poisoning by blocking the direct interaction between phosphoric acid and platinum, thereby maintaining catalytic activity at medium temperatures.
3Temperature
If protic ionic liquid is used as proton conductor, then the system can function at elevated temperatures, but the proton transport number remains low resulting in reduced electromotive force
Solution Approach 1:
The patent fundamentally changes the structural parameters of the proton conductor by transitioning from a simple protic ionic liquid to a structured metal organic framework within a polymer matrix. This structural transformation creates ordered channels with optimized dimensions and chemistry for proton transport. The MOF structure provides well-defined pathways with appropriate pore sizes and surface chemistry that dramatically enhance proton mobility compared to conventional ionic liquids, thereby increasing electromotive force while maintaining elevated temperature operation capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proton conductor with a higher proton transport number and improved heat resistance prevents the deterioration of power generation performance and maintains catalytic activity even at elevated temperatures, outperforming traditional protic ionic liquid-based systems.
Implementation Method 1
A proton conductor in contact with a catalyst containing platinum includes a cationic organic molecule, a metal ion, and an oxoacid anion. The cationic organic molecule, the metal ion, and the oxoacid anion form a coordination polymer.
Implementation Method 2
A protic ionic liquid containing the cationic organic molecule and the oxoacid anion is coordinated to the metal ion to form the coordination polymer.
Data Source
AI summary
A proton conductor is in contact with a catalyst containing platinum. The proton conductor includes a cationic organic molecule, a metal ion, and an oxoacid anion. A protic ionic liquid containing the cationic organic molecule and the oxoacid anion is coordinated to the metal ion to form a coordination polymer.